;; Copyright 2018, 2019 Google LLC
;;
;; Licensed under the Apache License, Version 2.0 (the License);
;; you may not use this file except in compliance with the License.
;; You may obtain a copy of the License at
;;
;;     http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an AS IS BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.

(library (rnrs mutable-pairs)
  (export set-car! set-cdr!)
  (import (rnrs))

  (define (set-car! p a)
    (if (pair? p)
        (%set-car! p a)
        (error 'set-car! "set-car!: not a pair")))
  (define (set-cdr! p d)
    (if (pair? p)
        (%set-cdr! p d)
        (error 'set-cdr! "set-cdr!: not a pair"))))
